1. Field of the Invention
This invention relates generally to mobile data terminals. More particularly, this invention relates to programmable mobile data terminals for sending and receiving predeterminedly formatted digitally encoded messages.
2. Description of the Prior Art
Mobile data terminals of the prior art have typically been of the type which have circuitry dedicated to performing a particular function. These circuits included circuits for servicing and scanning keyboards, circuits for storing and displaying characters, circuits for receiving messages, and circuits for transmitting messages. Each of these circuits is independent of the other circuits. This results in complicated, less reliable, expensive terminals, not optimally suited for use in the crowded environment of, for example, a law enforcement officer's vehicle. Since these systems use dedicated, discrete circuit components to perform the separate electronic functions when called upon, as described above, much of the dedicated circuitry lies idle and, being inflexible in application, is not suitable for use in performing other system functions.
With the growth of computerized law enforcement information systems, data on, for example, stolen vehicles, wanted persons, license plates, and outstanding warrants is available at local law enforcement headquarters in computer-based systems, which are oftentimes linked to State and National data bases. Very often inquiries into these data bases by an officer in the field is by means of voice communication to his dispatcher. The need for an improved mobile electronic data terminal by which an officer can more effectively communicate directly with a data base through an electronic dispatching system has long existed.